The present invention relates to a circuit arrangement of a household appliance.
According to the invention, the circuit arrangement is configured to generate a low-voltage, preferably in the form of a pulse-type low-voltage signal, to be supplied to a device of the electric household appliance at negligible low power consumption preferably less than 10 mW.
The circuit is particularly advantageous for reducing standby-mode energy consumption of an electric household appliance.
As is known, some last-generation electric household appliances are designed to switch to a standby or rest mode pending command to restart the operating cycle.
Though less than in operating mode, energy consumption of the electric loads and the main electronic control unit of the appliance in standby mode is still relatively high.
Accordingly, systems for reducing standby-mode energy consumption have been devised, in which the main electronic control unit selectively opens one or more switches, e.g. monostable relays, to disconnect the electric loads of the appliance from the power mains.
Systems of this sort have the drawback of having to keep the main electronic control unit powered with a low voltage, so that, albeit reduced, energy consumption fails to comply with last-generation electric household appliance energy consumption standards, which call for less than 1 watt standby energy consumption of the appliance.
To reduce energy consumption further, electric household appliances have been designed with systems which, in standby mode, set the power unit to low voltage to power the main electronic control unit in an idle state.
German Patent Application DE-102006054539B3, for example, relates to a system for generating low voltage to power a washing machine electronic control unit, wherein a low-voltage main power unit is designed to go from an active state, in which it supplies the electronic control unit with low voltage, to an idle state, in which it cuts off low-voltage supply to the electronic control unit, but still remains partly active so it can be reactivated by a control signal.
More specifically, in the above system, the low-voltage main power unit receives the control signal via a control input, and switches state alongside a change in state of the control signal.
The low-voltage main power unit is partly powered in the idle state, so as to detect the change in state of the control signal and reactivate quickly.
In other words, in the above system, the main power unit has to maintain power to its own internal electronic circuits responsible for detecting the change in state of the control signal and reactivating low voltage supply to the electronic control unit.